CN114835380A - Melting production process for inhibiting volatilization of borosilicate glass components - Google Patents

Abstract

The invention provides a melting production process for inhibiting the volatilization of borosilicate glass components. The process of the invention comprises the steps of: melting the raw material powder corresponding to the easily volatile components in the borosilicate glass to form a precursor glass; then mixing and melting the precursor glass and the remaining borosilicate glass raw material powder to obtain the borosilicate glass Glass. The present invention adopts the secondary melting method to separately melt the volatile components in the borosilicate glass formula into glass, and then introduce it into the borosilicate glass raw material in the form of glass, and replace the original formula with the form of glass The raw material powder greatly reduces the volatilization rate of elements such as boron, ensures the stability of the glass design components and the production process, and improves the uniformity, performance and quality of the glass.

Description

A melting production process for inhibiting the volatilization of borosilicate glass components

technical field

The invention belongs to the technical field of glass melting, and relates to a melting production process for inhibiting the volatilization of borosilicate glass components.

Background technique

At present, air pollution is still the most serious environmental protection problem in the world. Among them, the smog emitted by furnaces in the glass industry is one of the sources of environmental pollution, which continues to affect the living environment of human beings. One of the ways to reduce the combustion emissions of glass furnaces is to reduce the volatilization of raw materials and improve the efficiency of industrial production.

Borosilicate glass is a low-cost material, it is widely used in instrument glass, daily glass, optical glass, fireproof glass and other fields, which is also due to the many excellent properties of borosilicate glass, such as: good Chemical stability, thermal stability, mechanical properties, optical properties, low loss rate, etc. However, borosilicate glass requires a higher melting temperature, and some oxides are volatile, resulting in changes in the composition and properties of borosilicate glass, such as viscosity, density, liquidus temperature, and refractive index. As an important former oxide of borosilicate glass, B ₂ O ₃ has serious volatilization. According to reports, the mass loss of B ₂ O ₃ melting glass alone can reach 20%, and its volatilization rate will increase sharply when the moisture content in the raw material is higher, so some foreign manufacturers usually use anhydrous boric acid when producing boron glass. Or anhydrous borax can be introduced into B ₂ O ₃ , but this can only reduce the volatilization of a small part of boron oxide, which is very small. The volatilization of B ₂ O ₃ will cause the phenomenon of local high silicon content in the glass, reduce the uniformity of the glass, and directly affect the structure, performance and quality of the glass. As an isotropic supercooled liquid, the uniformity of glass determines its performance. Therefore, how to reduce the volatilization of elements such as boron, reduce production costs, and improve the uniformity, performance and quality of glass, has become the focus of the glass industry.

There are reports on reducing boron volatilization in the prior art, but most of them are to improve the structure of the glass furnace to reduce boron volatilization. For example, Chinese patent document CN107188393A discloses a melting furnace device for controlling the volatilization of boron in the production of borosilicate monolithic fireproof glass. It can reduce the volatilization of boron in the production of borosilicate monolithic fireproof glass, and can reduce the volatilization of boron by 5% to 15% at most. The invention reduces the volatilization of boron by improving the structure of the glass furnace, cannot fundamentally solve the problem of volatilization of boron by the process itself, and is not effective in reducing the volatilization of boron.

Therefore, it is worth further research to explore a process method to reduce the volatilization of elements such as boron, reduce production costs, and improve the uniformity, performance and quality of glass from the process itself.

SUMMARY OF THE INVENTION

Aiming at the deficiencies in the prior art, the present invention provides a melting production process for inhibiting the volatilization of borosilicate glass components. The invention mainly solves the defects existing in glass preparation by traditional melting method: the glass composition changes after volatilization of some elements (such as B, Na, etc.), the inhomogeneity of glass properties, and the reduction of glass quality and performance. The present invention adopts a secondary melting method, and the volatile components in the borosilicate glass formula are separately melted into glass, which is then introduced into the borosilicate glass raw material in the form of glass, and the original formula is replaced by the form of glass. The raw material powder greatly reduces the volatilization rate of elements such as boron, ensures the stability of the glass design components and the production process, and improves the uniformity, performance and quality of the glass.

The technical scheme of the present invention is as follows:

A melting production process for inhibiting the volatilization of borosilicate glass components, comprising the steps of:

(1) The raw material powder corresponding to the easily volatile components in the borosilicate glass is melted into the precursor glass;

(2) Then, the precursor glass and the remaining borosilicate glass raw material powder are mixed and melted to obtain borosilicate glass.

Preferably according to the present invention, in step (1), the borosilicate glass comprises the following components by mass percentage: SiO ₂ 60-85%, B ₂ O ₃ 5-17%, Na ₂ O+K ₂ O 4-15%, CaO 0.5-5%, Al ₂ O ₃ 2-10%.

Preferably, the borosilicate glass is prepared from the following raw materials: SiO ₂ , B ₂ O ₃ , K ₂ CO ₃ , Na ₂ CO ₃ , CaCO ₃ , and Al ₂ O ₃ .

Preferably, the raw materials corresponding to the easily volatile components in the borosilicate glass are B ₂ O ₃ and Na ₂ CO ₃ .

Preferably according to the present invention, in step (1), the preparation method of the precursor glass includes the steps of: mixing and melting the raw material powder corresponding to the easily volatile components in the borosilicate glass, cooling and forming, annealing and forming Shards get precursor glass.

Preferably, the mixing method is room temperature ball milling for 3-5 hours.

Preferably, the melting temperature is 900-1100°C, preferably 1000°C; the melting and holding time is 20-40min, preferably 30min; the melting temperature rise rate is 3-8°C/min; the annealing temperature is 300-500°C, preferably 400°C; annealing treatment time is 1-3h, preferably 2h. The present invention performs annealing treatment to relieve internal stress.

Preferably, the precursor glass is a block with a size of 0.5-1 cm.

Preferably according to the present invention, in step (1), after uniformly mixing the raw material powders corresponding to the easily volatile components in the borosilicate glass, 50%-100% of the total mass of the obtained powders is melted into the precursor glass. The raw materials corresponding to the remaining volatile components are added in the form of powder, followed by subsequent mixing and melting. Preferably, all the raw material powders corresponding to the easily volatile components in the borosilicate glass are melted to form the precursor glass.

Preferably according to the present invention, in step (2), the preparation method of borosilicate glass includes the steps of: mixing and melting the precursor glass and remaining borosilicate glass raw material powder, cooling and forming, and annealing to obtain borosilicate glass Salt glass.

Preferably, the melting temperature does not exceed 1580°C, preferably 1580°C; the melting and holding time is 1-3h, preferably 1.5h; the melting temperature rise rate is 3-8°C/min; the annealing temperature is 300-600°C, preferably 530℃, the annealing treatment time is 1-3h, preferably 2h.

The technical characteristics and beneficial effects of the present invention are as follows:

1. The present invention adopts a secondary melting method, and the volatile components in the borosilicate glass formula are separately melted into glass, and then introduced into the borosilicate glass raw material in the form of glass, and the original glass is replaced by the form of glass. The raw material powder in the formula greatly reduces the volatilization rate of elements such as boron, ensures the stability of the glass design components and the production process, and improves the uniformity, performance and quality of the glass.

2. The melting method of the present invention has a lower loss rate, reduces the loss of volatile components and energy loss, effectively improves energy utilization efficiency, and improves industrial production efficiency.

3. The present invention saves the consumption of raw material resources, and the introduced precursor glass fragments are used as a fluxing agent, which is helpful for the clarification and homogenization of the glass liquid. The borosilicate glass melted by the production process of the invention has excellent uniformity, wherein the bubble streaks are obviously reduced; the good uniformity ensures the stability of the glass performance and improves the use reliability of the glass; the properties of the obtained glass are and higher quality.

4. The invention has the advantages of simple production process, easy operation and low cost.

5. The specific size of the precursor glass of the present invention is favorable for mixing it with the remaining raw materials uniformly, thereby helping to ensure the uniformity of the borosilicate glass.

Description of drawings:

Fig. 1 is the X-ray diffraction (XRD) patterns of Glass0, 20, 50, 100 obtained in the embodiment of the present invention and the comparative example.

FIG. 2 is the scanning electron microscope (SEM) images of Glass0, 20, 50, and 100 obtained in the embodiment of the present invention and the comparative example.

FIG. 3 is the X-ray (EDS) energy spectrum of Glass0 obtained in Comparative Example 1 of the present invention.

FIG. 4 is the X-ray (EDS) energy spectrum of Glass100 obtained in Example 1 of the present invention.

Detailed ways

The present invention will be further described below through specific embodiments and in conjunction with the accompanying drawings, but is not limited thereto.

The raw materials used in the examples are all chemical reagents with a purity of 99.99%, commercially available products unless otherwise specified.

Example 1

A melting production process for inhibiting the volatilization of borosilicate glass components, the borosilicate glass includes the following components by mass percentage: SiO ₂ 68%, B ₂ O ₃ 13%, Na ₂ O 10%, K ₂ O 2%, CaO 2%, Al ₂ O ₃ 5%. The raw materials used are: SiO ₂ , B ₂ O ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , and Al ₂ O ₃ .

The preparation includes the following steps:

(1) Preparation of precursor glass: convert the amount of raw materials according to the above component ratios, weigh B ₂ O ₃ and Na ₂ CO ₃ respectively, place them on a ball mill and mix them evenly at room temperature for 4 hours, and place the raw materials in a muffle furnace and heat to 1000 ℃ for melting A glass melt is formed, the melting heating rate is 5°C/min, the melting holding time is 30 min, and the melt is quickly poured onto a copper plate for cooling and forming to obtain a block glass. The formed bulk glass is then annealed at 400°C for 2 hours to eliminate internal stress. The annealed glass is made into a random block with a size of 0.5-1 cm to obtain a precursor glass.

(2) Convert the amount of raw materials according to the above component ratio, mix the precursor glass prepared in step (1) and the remaining raw materials evenly, heat to 1580 ° C for melting and heat preservation for 1.5 h, the melting temperature rise rate is 5 ° C/min, after cooling and forming, 530 ° C After annealing for 2h, borosilicate glass was obtained, which was recorded as Glass100.

According to the quality change before and after melting, it is concluded that the loss of borosilicate glass Glass100 is only 5.08g, and the volatilization rate is 4.74%. This shows that the incorporation of precursor glass blocks during the melting process can effectively inhibit the volatilization of some raw materials. Among them, the calculation formula of the volatilization rate is as follows:

Example 2

A melting production process for inhibiting the volatilization of borosilicate glass components, the borosilicate glass includes the following components by mass percentage: SiO ₂ 68%, B ₂ O ₃ 13%, Na ₂ O 10%, K ₂ O 2%, CaO 2%, Al ₂ O ₃ 5%. The raw materials used are: SiO ₂ , B ₂ O ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , and Al ₂ O ₃ .

The preparation includes the following steps:

(1) Preparation of precursor glass: convert the amount of raw materials according to the above component ratios, weigh B ₂ O ₃ and Na ₂ CO ₃ respectively, and place them on a ball mill for uniform mixing at room temperature for 4 hours; 50% of the total mass of the obtained powder is placed in a muffle furnace Heating to 1000°C and melting into glass melt, the melting heating rate is 5°C/min, the melting holding time is 30min, and the melt is quickly poured onto a copper plate for cooling and forming to obtain block glass. The formed bulk glass is then annealed at 400°C for 2 hours to eliminate internal stress. The annealed glass is made into a random block with a size of 0.5-1 cm to obtain a precursor glass.

(2) Convert the amount of raw materials according to the proportion of the above components, mix the precursor glass prepared in step (1), the mixed powder of remaining B ₂ O ₃ and Na ₂ CO ₃ , and other raw material powders evenly, and heat to 1580 ° C for melting and heat preservation for 1.5 h, The melting and heating rate was 5°C/min. After cooling and forming, borosilicate glass was obtained by annealing at 530°C for 2 hours, which was recorded as Glass50.

The loss and volatilization rate were calculated according to the method of Example 1, and it was concluded that the loss of the borosilicate glass Glass50 was 8.34 g, and the volatilization rate reached 7.79%. This shows that the incorporation of 50% of the precursor glass block in the melting process has a certain inhibitory effect on the volatilization of some raw materials.

Comparative Example 1

A melting production process for inhibiting the volatilization of borosilicate glass components, the borosilicate glass includes the following components by mass percentage: SiO ₂ 68%, B ₂ O ₃ 13%, Na ₂ O 10%, K ₂ O 2%, CaO 2%, Al ₂ O ₃ 5%. The raw materials used are: SiO ₂ , B ₂ O ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , and Al ₂ O ₃ . .

The preparation includes the following steps:

Calculate the amount of raw materials according to the above component ratios, mix the raw materials evenly, heat to 1580 °C for melting and heat preservation for 1.5 hours, and the melting temperature rise rate is 5 °C/min. for Glass0.

The loss and volatilization rate were calculated according to the method of Example 1, and it was concluded that the loss of the borosilicate glass Glass0 was 11.60 g, and the volatilization rate reached 10.83%. This shows that the volatilization of raw materials (oxides such as Na ₂ O, B ₂ O ₃ , etc.) during the melting process is more serious.

Comparative Example 2

A melting production process for inhibiting the volatilization of borosilicate glass components, the borosilicate glass includes the following components by mass percentage: SiO ₂ 68%, B ₂ O ₃ 13%, Na ₂ O 10%, K ₂ O 2%, CaO 2%, Al ₂ O ₃ 5%. The raw materials used are: SiO ₂ , B ₂ O ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , and Al ₂ O ₃ .

The preparation includes the following steps:

(1) Preparation of precursor glass: convert the amount of raw materials according to the above component ratios, weigh B ₂ O ₃ and Na ₂ CO ₃ respectively, and place them on a ball mill for uniform mixing at room temperature for 4 hours; 20% of the total mass of the obtained powder is placed in a muffle furnace Heating to 1000°C and melting into glass melt, the melting heating rate is 5°C/min, the melting holding time is 30min, and the melt is quickly poured onto a copper plate for cooling and forming to obtain block glass. The formed bulk glass is then annealed at 400°C for 2 hours to eliminate internal stress. The annealed glass is made into a random block with a size of 0.5-1 cm to obtain a precursor glass.

(2) Convert the amount of raw materials according to the proportion of the above components, mix the precursor glass prepared in step (1), the mixed powder of remaining B ₂ O ₃ and Na ₂ CO ₃ , and other raw material powders evenly, and heat to 1580 ° C for melting and heat preservation for 1.5 h, The melting and heating rate was 5°C/min. After cooling and forming, borosilicate glass was obtained by annealing at 530°C for 2 hours, which was recorded as Glass20.

The loss and volatilization rate were calculated according to the method of Example 1, and it was concluded that the loss of the borosilicate glass Glass20 was 10.29 g, and the volatilization rate reached 9.61%. This shows that the incorporation of 20% precursor glass blocks in the melting process has a certain inhibitory effect on the volatilization of some raw materials, but the inhibitory effect is weak.

Test Example 1

Analysis of sample volatilization rate

The volatilization rate test was carried out on the preparation methods of the examples and the comparative examples. According to the mass change before and after melting, the volatilization amount and volatilization rate were tested. The results are shown in Table 1.

Table 1

From Table 1, it is found that the incorporation of different proportions of precursor glass will affect the loss rate of borosilicate glass. When the proportion of the precursor glass introduced is larger, the loss rate of the borosilicate glass is lower, which means that the introduction of the precursor glass can greatly reduce the volatilization of B ₂ O ₃ and Na ₂ CO ₃ . In particular, when B ₂ O ₃ and Na ₂ CO ₃ in the raw materials are completely introduced in the form of precursor glass, the volatilization rate of finally obtained borosilicate glass Glass100 is only 4.74%.

Test Example 2

Crystal phase analysis

The glass samples obtained in the examples and comparative examples were subjected to X-ray diffraction (XRD) analysis, as shown in FIG. 1 .

The glass samples obtained in the examples and the comparative examples all show diffuse steamed bread peaks without sharp diffraction peaks, indicating that there is no crystalline phase in the sample structure, and it is in an amorphous state, which indicates that the melted borosilicate glass is pure glass. .

Test Example 3

Sample morphology and composition analysis

The glass samples prepared in the examples and the comparative examples were tested by scanning electron microscope (SEM), as shown in FIG. 2 .

It can be seen from Figure 2 that the surface of the Glass0 sample is uneven, and there are some unevenly distributed particles of 50-200 nm on the surface. With the increase in the amount of the precursor glass added, the glass surface is flatter and more uniform. That is, the greater the proportion of the precursor glass introduced into the borosilicate glass sample, the less surface defects. This shows that the introduction of the precursor glass bulk into the raw material can reduce the volatilization of oxides such as B ₂ O ₃ and Na ₂ O, and is beneficial to the uniformity of the glass melting process.

X-ray energy spectroscopy (EDS) tests were performed on the glass samples prepared in the examples and comparative examples, as shown in FIGS. 3 and 4 . Through line scanning of the sample, the distribution of the intensity content of each element in the glass was obtained. As can be seen from Figure 3, the content of each element of Glass0 fluctuates significantly, especially the K, Al, O, Si elements are obviously unevenly distributed, which indicates that the volatilization of Glass0 raw materials during the melting process causes local element enrichment or lack, resulting in molding The glass exhibits inhomogeneity. In Figure 4, the content of each element in Glass100 changes little, with only small fluctuations, which shows that the incorporation of precursor glass reduces the volatilization rate of the glass, which makes the glass melt more uniformly during the melting process, and improves the uniformity of the glass. sex. Good uniformity ensures the stability of glass performance and improves the reliability of glass in use. In terms of loss rate and uniformity, the glass obtained by incorporating the precursor glass is superior to the glass obtained by not incorporating the precursor glass.

Claims (10)

1. A melting production process for inhibiting the volatilization of borosilicate glass components, comprising the steps of: (1) The raw material powder corresponding to the easily volatile components in the borosilicate glass is melted into the precursor glass; (2) Then, the precursor glass and the remaining borosilicate glass raw material powder are mixed and melted to obtain borosilicate glass. 2 . The melting production process for inhibiting volatilization of borosilicate glass components according to claim 1 , wherein, in step (1), the borosilicate glass comprises the following composition by mass percentage: SiO ₂ 60 . -85%, B2O3 5-17%, Na2O ₊ K2O _4-15 %, CaO 0.5-5 _% , _{Al2O3 2-10 %} . 3. The melting production process for inhibiting the volatilization of borosilicate glass components according to claim 2, wherein the borosilicate glass is prepared from the following raw materials: SiO ₂ , B ₂ O ₃ , Na ₂ CO _3. K ₂ CO ₃ , CaCO ₃ , Al ₂ O ₃ . 4 . The melting production process for inhibiting the volatilization of borosilicate glass components according to claim 2 , wherein the raw materials corresponding to the easily volatile components in the borosilicate glass are B ₂ O ₃ and Na ₂ CO ₃ . . 5 . The melting production process for inhibiting the volatilization of borosilicate glass components according to claim 1 , wherein in step (1), the preparation method of the precursor glass comprises the step of: absorbing easily volatile substances in the borosilicate glass. 6 . The raw material powders corresponding to the components are mixed, melted, cooled and formed, and then annealed and made into pieces to obtain the precursor glass. 6 . The melting production process for inhibiting volatilization of borosilicate glass components according to claim 5 , wherein the mixing method is room temperature ball milling for 3-5 hours. 7 . 7. The melting production process for inhibiting the volatilization of borosilicate glass components according to claim 5, wherein the melting temperature is 900-1100°C, preferably 1000°C; the melting holding time is 20-40min, preferably 30min ; The melting heating rate is 3-8°C/min; the annealing temperature is 300-500°C, preferably 400°C; the annealing time is 1-3h, preferably 2h. 8 . The melting production process for inhibiting the volatilization of borosilicate glass components according to claim 1 , wherein the precursor glass is a block with a size of 0.5-1 cm. 9 . 9 . The melting production process for inhibiting the volatilization of borosilicate glass components according to claim 1 , wherein in step (1), the raw material powders corresponding to the easily volatile components in the borosilicate glass are mixed uniformly. Then, 50%-100% of the total mass of the obtained powder is melted to form the precursor glass; preferably, all the raw material powders corresponding to the easily volatile components in the borosilicate glass are melted to form the precursor glass. 10 . The melting production process for inhibiting volatilization of borosilicate glass components according to claim 1 , wherein in step (2), the preparation method for borosilicate glass comprises the steps of: mixing the precursor glass with the remaining borosilicate glass. 11 . The raw material powder of salt glass is mixed and melted, cooled and formed, and then annealed to obtain borosilicate glass; Preferably, the melting temperature does not exceed 1580°C, preferably 1580°C; the melting and holding time is 1-3h, preferably 1.5h; the melting temperature rise rate is 3-8°C/min; the annealing temperature is 300-600°C, preferably 530℃, the annealing treatment time is 1-3h, preferably 2h.

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